There is a growing focus upon CNS factors in antisocial behavior. As yet, this area of research is unguided by theory, but several studies have reported that delinquents evidence a variety of cognitive deficits, as assessed by neuropsychological tests. This literature is troubled by methodological shortcomings: small N's, cross-sectional design, bias from highly-selected incarcerated or referred subjects, post-hoc choice of tests for research use, and failure to demonstrate the specificity of the deficits to delinquency, rather than to ADD or reading disability. This project was designed to evaluate the possibility that some specific patterns of cognitive deficit are predictive of delinquent behavior, while using self-reported delinquent behavior, a large unselected cohort, and a research battery of tests to avoid most of the problems characteristic of earlier research. The birth cohort studied comprises the 1037 subjects of the longitudinal Dunedin (New Zealand) Multidisciplinary Health and Development Study. Neurological, health, educational, psychological, social and family data have been collected for the cohort since birth. The project's first three years, supported by a NIH New Investigator Award, consisted of data collection when the subjects were 13 years old, and has produced six papers to date. Analyses are yielding evidence that patterns of neuropsychological deficit do exist which relate to self-report early adolescent delinquent behavior. The proposed project is a follow-up, designed to collect self-report delinquency data at age 15 and police records of official delinquency at ages 15, 16, and 17. The ultimate aim of the project is to test the efficacy of neuropsychological variables, in concert with other pertinent variables, for discriminating nondeliquents, minor delinquents who desist early on, and delinquents who go on to develop serious and recidivistic juvenile offense careers. Knowledge of delinquency-related patterns of cognitive dysfunction may provide information useful toward goals of: (1) Increased understanding of the etiology of delinquency, (2) Identification of specific delinquency-related patterns of deficit which may be targeted for preventive intervention, (3) Addition to the growing list of warning signs for early identification of children at risk for developing seriously delinquent lifestyles, and (4) Provision of information in support of theory construction.